In principle, for the in-line supply of voltage to an electrical or electronic apparatus located in the region of a DC line, it is possible to arrange in the line an electrical component having an electrical resistance. The voltage drop produced by this electrical resistance could be used directly or after stepping-up for the in-line voltage supply.
WO 2006/125664 A1 discloses a circuit breaker. The circuit breaker is intended for a solar module in which a plurality of solar cells are connected in series, some of which are operating normally while some are operating in shadow. The circuit breaker can be connected in parallel with the plurality of solar cells to form a bypass path. In addition to a bypass diode, which is standard practice in this position in solar modules, the circuit breaker comprises a semiconductor switch connected in parallel with the bypass diode, the intrinsic freewheeling diode of which switch is oriented parallel to the bypass diode, i.e. the two diodes have the same forward-bias and reverse-bias directions along the bypass path. The semiconductor switch is driven to open when the parallel bypass diodes conduct a current in the forward-bias direction in order to reduce the power dissipation occurring in the bypass diode and associated heat generation. A supply circuit for providing the control voltage for the semiconductor switch is designed as a charging circuit for an energy store, which circuit steps up a voltage available across the bypass diode during shadow to a higher voltage for driving the semiconductor switch. The intention is to be able to use the supply voltage available across the bypass diode during shadow not only to drive the controllable bypass element but also to supply further circuits.
US 2011/0279937 A1 discloses a circuit breaker in which there is a MOSFET containing a freewheeling diode. The circuit breaker comprises a control circuit for controlling the MOSFET. The control circuit includes, inter alia, a series circuit which consists of a resistor, a diode and a capacitor and is connected in parallel with the MOSFET. The diode in the series circuit allows a current flow in the forward-bias direction of the diode for the purpose of charging the capacitor, while preventing a current flow in the opposite direction, which would discharge the capacitor again. The voltage drop across the capacitor thereby provides a supply voltage for supplying voltage to the control circuit.